/*
* Conditions Of Use 
* 
* This software was developed by employees of the National Institute of
* Standards and Technology (NIST), an agency of the Federal Government.
* Pursuant to title 15 Untied States Code Section 105, works of NIST
* employees are not subject to copyright protection in the United States
* and are considered to be in the public domain.  As a result, a formal
* license is not needed to use the software.
* 
* This software is provided by NIST as a service and is expressly
* provided "AS IS."  NIST MAKES NO WARRANTY OF ANY KIND, EXPRESS, IMPLIED
* OR STATUTORY, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTY OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, NON-INFRINGEMENT
* AND DATA ACCURACY.  NIST does not warrant or make any representations
* regarding the use of the software or the results thereof, including but
* not limited to the correctness, accuracy, reliability or usefulness of
* the software.
* 
* Permission to use this software is contingent upon your acceptance
* of the terms of this agreement
*  
* .
* 
*/
 /****************************************************************************
 * Product of NIST/ITL Advanced Networking Technologies Division (ANTD).    *
 ****************************************************************************/
package gov.nist.javax.sip.header;
import gov.nist.core.*;
import javax.sip.header.AcceptLanguageHeader;
import javax.sip.InvalidArgumentException;
import java.util.Locale;

/**
 * Accept Language body.
 *
 * @author M. Ranganathan 
 * @version 1.2 $Revision: 1.6 $ $Date: 2006/11/12 21:52:38 $
 * @since 1.1
 *
 *
 * <pre>
 * HTTP RFC 2616 Section 14.4
 * Accept-Language = "Accept-Language" ":"
 *                         1#( language-range [ ";" "q" "=" qvalue ] )
 *       language-range  = ( ( 1*8ALPHA *( "-" 1*8ALPHA ) ) | "*" )
 *
 * </pre>
 *
 * @see AcceptLanguageList
 */
public final class AcceptLanguage
	extends ParametersHeader
	implements AcceptLanguageHeader {

	/**
	 * Comment for <code>serialVersionUID</code>
	 */
	private static final long serialVersionUID = -4473982069737324919L;
	/** languageRange field
	 */
	protected String languageRange;

	/** default constructor
	 */
	public AcceptLanguage() {
		super(NAME);
	}

	/** Encode the value of this header to a string.
	 *@return  encoded header as a string.
	 */
	protected String encodeBody() {
		StringBuffer encoding = new StringBuffer();
		if (languageRange != null) {
			encoding.append(languageRange);
		}
		if (!parameters.isEmpty()) {
			encoding.append(SEMICOLON).append(parameters.encode());
		}
		return encoding.toString();
	}

	/** get the LanguageRange field
	 * @return String
	 */
	public String getLanguageRange() {
		return languageRange;
	}

	/** get the QValue field. Return -1 if the parameter has not been 
	 * set.
	 * @return float
	 */

	public float getQValue() {
		if (!hasParameter("q"))
			return -1;
		return ((Float) parameters.getValue("q")).floatValue();
	}

	/**
	 * Return true if the q value has been set.
	 * @since 1.0
	 * @return boolean
	 */
	public boolean hasQValue() {
		return hasParameter("q");
	}

	/**
	 * Remove the q value.
	 * @since 1.0
	 */
	public void removeQValue() {
		removeParameter("q");
	}

	/**
	 * Set the languageRange.
	 *
	 * @param languageRange is the language range to set.
	 *
	 */
	public void setLanguageRange(String languageRange) {
		this.languageRange = languageRange.trim();
	}

	/**
	 * Sets q-value for media-range in AcceptLanguageHeader. Q-values allow the
	 *
	 * user to indicate the relative degree of preference for that media-range,
	 *
	 * using the qvalue scale from 0 to 1. If no q-value is present, the
	 *
	 * media-range should be treated as having a q-value of 1.
	 *
	 *
	 *
	 * @param q The new float value of the q-value, a value of -1 resets
	 * the qValue.
	 *
	 * @throws InvalidArgumentException if the q parameter value is not
	 *
	 * <code>-1</code> or between <code>0 and 1</code>.
	 *
	 */
	public void setQValue(float q) throws InvalidArgumentException {
		if (q < 0.0 || q > 1.0)
			throw new InvalidArgumentException("qvalue out of range!");
		if (q == -1)
			this.removeParameter("q");
		else
			this.setParameter(new NameValue("q", new Float(q)));
	}

	/**
	 * Gets the language value of the AcceptLanguageHeader.
	 *
	 *
	 *
	 * @return the language Locale value of this AcceptLanguageHeader
	 *
	 */
	public Locale getAcceptLanguage() {
		if (this.languageRange == null)
			return null;
		else {
			int dash = languageRange.indexOf('-');
			if (dash>=0) {
				return new Locale( languageRange.substring(0,dash), languageRange.substring(dash+1) );
			} else return new Locale( this.languageRange );
		}
	}

	/**
	 * Sets the language parameter of this AcceptLanguageHeader.
	 *
	 *
	 *
	 * @param language - the new Locale value of the language of
	 *
	 * AcceptLanguageHeader
	 *
	 *
	 */
	public void setAcceptLanguage(Locale language) {
		// JvB: need to take sub-tag into account
		if ( "".equals(language.getCountry())) {
			this.languageRange = language.getLanguage();
		} else {
			this.languageRange = language.getLanguage() + '-' + language.getCountry();
		}
	}

}
